Municipal pipeline groove excavation supporting structure in old urban area and construction method of municipal pipeline groove excavation supporting structure

Abstract

The invention discloses an excavation and support structure for municipal pipeline grooves in old urban areas and a construction method thereof, which are suitable for construction under the working conditions of deeper groove excavation depth, narrow surrounding roads, larger traffic flow, limited operation conditions and complex surrounding environment, especially under the condition of no sloping support condition on site. Under the condition that the supporting of the steel sheet piles is not suitable, by optimizing the construction method of a traditional reverse construction method, retaining walls on the two sides, a plurality of reinforced concrete transverse supporting walls and steel supports form a plurality of stable structures to balance the lateral soil pressure of surrounding soil bodies, the construction difficulty is greatly reduced, and long-term operation and maintenance are facilitated; and better construction safety, economical efficiency and operability are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of municipal integrated pipelines, and in particular relates to a municipal pipeline trench excavation support structure in an old urban area and a construction method thereof. Background Art

[0002] In the process of renewing old urban projects, the excavation of municipal integrated pipeline trenches is the most important part of the project construction. The excavation of the foundation pit of the municipal pipeline network project is the first step to ensure the safety and stability of the pipeline network construction. Its quality directly affects the reliability and durability of the entire system. A reasonable foundation pit excavation plan can not only improve construction efficiency, but also effectively protect the environment, achieving a win-win situation of economic and social benefits.

[0003] At present, the main support methods for municipal integrated pipeline trenches are slope support and steel sheet pile support, which are greatly constrained by the surrounding traffic conditions and geological conditions. With the rapid development of urban renewal projects, integrated pipeline renewal is getting closer and closer to the front end of the pipeline, penetrating into densely populated areas, traffic congested areas, and areas with complex buildings and structures. The traditional slope support and steel sheet pile support methods have high requirements on construction site conditions and construction process technology. In the complex working environment of old urban renewal projects, especially under the conditions of frequent interweaving of working surfaces and processes, their application is greatly restricted. Summary of the invention

[0004] In order to overcome the technical problems in the prior art, the present invention provides a municipal pipeline trench excavation support structure in old urban areas, which solves the above-mentioned technical problems by changing the structural concrete grade and reinforcement density to increase the strength and rigidity of the support structure, and by adding steel-steel bracing to strengthen the overall stability of the support structure.

[0005] A supporting structure for excavating a municipal pipeline trench in an old urban area includes a lock, a retaining wall, a cross partition wall, and steel braces. The strength and rigidity of the supporting structure can be increased by changing the structural concrete grade and the reinforcement density, and the overall stability of the supporting structure can be enhanced by adding steel braces.

[0006] In the above-mentioned old urban municipal pipeline trench excavation support structure, the distance between adjacent retaining walls is within 1 meter, and 300mm of longitudinal steel bars of each circle of retaining walls are reserved at the bottom.

[0007] In the above-mentioned old urban municipal pipeline trench excavation support structure, the steel brace is a steel structure, and the overall stability of the support structure is enhanced by changing the model and interface size of the steel structure.

[0008] A construction method for excavating a supporting structure for a municipal pipeline trench in an old urban area, the construction method comprising the following construction steps:

[0009] S1: Pavement cutting and demolition: For the demolition of the existing cement concrete pavement, it is necessary to first locate and lay out the lines according to the design drawings and the slope coefficient, and then use a seam cutter to cut the concrete panel. After the seam cutting is completed, the hydraulic rock crusher will crush the pavement. After the crushing is completed, a backhoe excavator will be used to load the concrete debris and transport it to the waste dump;

[0010] S2: Lock mouth construction: After the original road surface is cut and broken, a retaining wall needs to be built outside the lock mouth before the foundation pit is excavated to prevent rainwater from flowing into the foundation pit. The lock mouth construction sequence is: leveling the site → measuring and setting out → building retaining walls → excavating trenches → implanting steel bars → tying steel bars → supporting formwork → pouring lock mouth concrete → maintenance. The top surface elevation of the lock mouth is consistent with the top surface elevation of the roadbed;

[0011] S3: Construction of the first section of retaining wall and transverse partition wall: The construction sequence is measurement and positioning → trench excavation → trimming retaining wall → tying retaining wall and inner support steel bars → retaining wall and inner support formwork → center correction → pouring retaining wall concrete → curing → demoulding. The first section of retaining wall and transverse partition wall must be constructed simultaneously with the lock mouth;

[0012] S4: Second section retaining wall and steel bracing construction: The construction sequence is measurement and positioning → trench excavation → trimming retaining wall → retaining wall reinforcement binding → retaining wall formwork → center correction → pouring retaining wall concrete → curing → removing formwork → steel bracing installation;

[0013] S5: Repeat S3 and S4 to the design elevation. The retaining wall needs to be poured in time with the excavation progress. The distance between each section is strictly controlled within 1 meter. The longitudinal reinforcement of each circle of retaining wall is reserved 300mm at the bottom as the welding anchor section with the next section of retaining wall reinforcement. The recommended excavation depth for each cycle is not more than 1m, the demolding time is not less than 24h, and the concrete strength is not less than the design strength before the next section of earthwork excavation can be carried out;

[0014] S6: Manual pipe laying is adopted. The main construction sequence is to check the socket → clean the pipe → preheat the socket → install the socket. Before stabilizing the pipe, the foundation design elevation and centerline position should be checked. The pipe can be stabilized only after it meets the design and specification requirements. At the same time, the elevation and centerline of the pipeline installation should be measured and determined. For pipes with larger nominal diameters, it is recommended to use manual hoists and other lifting tools for installation, or use excavators or other thrusts to slowly insert the sockets;

[0015] S7: After the pipeline is laid, the trench is backfilled after passing the closed water test. The trench backfilling and steel support removal are carried out simultaneously. After backfilling to the top elevation of the lock mouth, the original road surface is restored;

[0016] S8: After other integrated pipelines are put into the ground and the foundation pit is excavated and pipelines are laid, the top of the inverted well wall is closed and the construction of the integrated pipeline corridor is completed.

[0017] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0018] 1. The construction method of the present invention has the characteristics of wide application range, high construction efficiency, stable structure and changeable support types. When it crosses the existing road, it can also fully cooperate with the steel temporary bridge erection process, through the underground pipeline suspension protection and other processes, effectively improve the safety and quality of the trench support structure and the surrounding building structure, shorten the construction period, and has important display significance;

[0019] 2. In the later stage, it can be used as a supporting structure for pipeline maintenance, renewal and other situations that require secondary construction, or after closing the top plate of the supporting structure, it can be directly used as the main structure of the integrated pipeline corridor for underground integrated pipelines, giving full play to its advantages of combining permanent and temporary functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0021] Figure 1 A top view of a trench excavation support structure for municipal pipelines in old urban areas according to the present invention;

[0022] Figure 2 The trench layout section of the municipal pipeline trench excavation in the old urban area according to the embodiment of the present invention Figure 1 ;

[0023] Figure 3 The trench layout section of the municipal pipeline trench excavation in the old urban area according to the embodiment of the present invention Figure 2 ;

[0024] Figure 4 A cross-sectional view of the comprehensive pipeline reconstruction layout of the municipal pipelines in old urban areas according to an embodiment of the present invention;

[0025] In the figure: 1-locking mouth, 2-wall protection, 3-cross partition wall, 4-steel bracing. DETAILED DESCRIPTION

[0026] like Figure 1 As shown, a top view of a municipal pipeline trench excavation support structure in an old urban area according to the present invention includes a lock 1, a protective wall 2, a cross partition wall 3 and a steel brace 4. The strength and rigidity of the support structure can be increased by changing the structural concrete grade and the reinforcement density, and the overall stability of the support structure can be enhanced by adding steel braces.

[0027] like Figure 2 and Figure 3 As shown in the figure, it is a cross-sectional view of the trench layout of the municipal pipeline trench excavation in the old urban area according to an embodiment of the present invention. The construction method mainly includes:

[0028] Step 1: Cut and remove the road surface. Remove the existing cement concrete road surface, locate and lay out the lines according to the design drawings and slope coefficients, use a seam cutter to cut the concrete panel first, and then use a hydraulic rock crusher to break the road surface. After breaking, use a backhoe excavator to load the concrete slag and transport it to the waste dump;

[0029] Step 2: After the original road surface is cut and broken, a retaining wall needs to be built outside the lock 1 before the foundation pit is excavated to prevent rainwater from flowing into the foundation pit. The construction sequence of the lock 1 is: leveling the site → measuring and setting out → building retaining walls → excavating trenches → implanting steel bars → tying steel bars → supporting formwork → pouring lock 1 concrete → curing. The top elevation of the lock 1 is consistent with the top elevation of the roadbed.

[0030] Step 3: Construction of the first section of retaining wall 2 and transverse partition wall 3: The construction sequence is measurement and positioning → trench excavation → trimming retaining wall 2 → binding of retaining wall 2 and inner support steel bars → formwork of retaining wall 2 and inner support → center correction → pouring of retaining wall 2 concrete → curing → demoulding. The first section of retaining wall 2 and transverse partition wall 3 need to be constructed simultaneously with lock mouth 1;

[0031] Step 4: Construction of the secondary retaining wall 2 and steel brace 4: The construction sequence is measurement and positioning → trench excavation → trimming retaining wall 2 → reinforcement binding of retaining wall 2 → formwork support of retaining wall 2 → center correction → pouring concrete for retaining wall 2 → maintenance → demoulding → installation of steel brace 4;

[0032] Step 5: Repeat steps S3 and S4 to the design elevation. The retaining wall 2 needs to be cast in time with the excavation progress. The distance between each section is strictly controlled within 1 meter. The longitudinal reinforcement of each circle of the retaining wall 2 is reserved for 300mm at the bottom as the welding anchor section with the reinforcement of the next section of the retaining wall 2. The recommended excavation depth for each cycle is not more than 1m, the demolding time is not less than 24h, and the concrete strength is not less than the design strength before the next section of earthwork excavation can be carried out;

[0033] Step 6: Manual pipe laying is adopted. The main construction sequence is to check the socket → clean the pipe → preheat the socket → install the socket. Before stabilizing the pipe, the foundation design elevation and centerline position should be checked. The pipe can be stabilized only after it meets the design and specification requirements. At the same time, the elevation and centerline of the pipeline installation should be measured and determined;

[0034] Step 7: After the pipeline is laid, the trench is backfilled after passing the closed water test. The trench backfilling and steel support 4 removal are carried out simultaneously. After backfilling to the top elevation of the lock mouth 1, the original road surface is restored. Figure 4 As shown, it is a cross-sectional view of pipeline reconstruction layout;

[0035] Step 8: After other integrated pipelines are put into the ground and the foundation pit is excavated and pipelines are laid, the top of the inverted well wall is closed and the construction of the integrated pipeline corridor is completed.

Claims

1. A trench excavation support structure for municipal pipelines in old urban areas, characterized in that: The invention comprises a lock (1), a retaining wall (2), a transverse partition wall (3) and a steel brace (4). The strength and rigidity of the support structure can be increased by changing the structural concrete grade and the reinforcement density. The overall stability of the support structure can be enhanced by adding the steel brace (4). The lock (1), the retaining wall (2) and the transverse partition wall (3) are all reinforced concrete structures. The safety factor of the support structure can be enhanced by adjusting the thickness, grade and reinforcement ratio of the structure.

2. The trench excavation support structure for municipal pipelines in old urban areas according to claim 1 is characterized in that: The distance between adjacent retaining walls (2) is within 1 meter, and 300 mm of longitudinal reinforcement is reserved at the bottom of each circle of retaining wall (2).

3. The trench excavation support structure for municipal pipelines in old urban areas according to claim 1 is characterized in that: The steel brace (4) is a steel structure, and the overall stability of the support structure is enhanced by changing the model and interface size of the steel structure.

4. A construction method for excavating and supporting structures for municipal pipeline trenches in old urban areas according to any one of claims 1 to 3, characterized in that: The construction method includes the following steps: S1: Pavement cutting and demolition: demolish the existing cement concrete pavement, position and lay out the lines according to the design drawings and slope coefficient, use a seam cutter to cut the concrete panel first, and then use a hydraulic rock crusher to break the pavement. After the breaking is completed, use a backhoe excavator to load the concrete slag and transport it to the waste dump; S2: Lock mouth (1) construction. After the original road surface is cut and broken, a retaining wall needs to be built outside the lock mouth (1) before the foundation pit is excavated to prevent rainwater from flowing into the foundation pit. The construction sequence of the lock mouth (1) is: leveling the site → measuring and setting out → building retaining walls → excavating trenches → implanting steel bars → tying steel bars → supporting formwork → pouring lock mouth (1) concrete → curing. The top surface elevation of the lock mouth (1) is consistent with the top surface elevation of the roadbed. S3: Construction of the first section of retaining wall (2) and transverse diaphragm (3): The construction sequence is measurement and positioning → trench excavation → trimming retaining wall (2) → reinforcement binding of retaining wall (2) and inner support → formwork of retaining wall (2) and inner support → center correction → pouring retaining wall (2) concrete → curing → demoulding. The first section of retaining wall (2) and transverse diaphragm (3) need to be constructed simultaneously with the locking mouth (1); S4: Construction of the secondary retaining wall (2) and steel bracing (4): The construction sequence is measurement and positioning → trench excavation → trimming the retaining wall (2) → reinforcement binding of the retaining wall (2) → formwork support for the retaining wall (2) → center correction → pouring the retaining wall (2) concrete → curing → demoulding → installation of steel bracing (4); S5: Repeat steps S3 and S4 to the design elevation. The retaining wall (2) needs to be cast in time with the excavation progress. The distance between each section is strictly controlled within 1 meter. The longitudinal reinforcement of each circle of the retaining wall (2) is reserved for 300mm at the bottom as a welding anchoring section with the reinforcement of the next section of the retaining wall (2). The excavation depth of each cycle is not more than 1m, the demoulding time is not less than 24h, and the concrete strength is not less than the design strength before the next section of earthwork excavation can be carried out; S6: Manual pipe laying is adopted. The main construction sequence is to check the socket → clean the pipe → preheat the socket → install the socket. Before stabilizing the pipe, the foundation design elevation and centerline position should be checked. The pipe can be stabilized only after it meets the design and specification requirements. At the same time, the elevation and centerline of the pipeline installation should be measured and determined; S7: After the pipeline is laid, the trench is backfilled after passing the water-tightness test. The trench backfilling and the removal of the steel brace (4) are carried out simultaneously. After backfilling to the top elevation of the lock mouth (1), the original road surface is restored; S8: After other integrated pipelines are put into the ground and the foundation pit is excavated and pipelines are laid, the top of the inverted well wall is closed and the construction of the integrated pipeline corridor is completed.

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